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United States Patent |
5,585,876
|
Kobayashi
|
December 17, 1996
|
Photographic camera
Abstract
A photographic camera has a film cartridge chamber, a film take-up chamber,
a film feed passage formed between a film window on a camera body and a
pressure plate on a camera back and a film feed mechanism. A film
cartridge in which a roll film is entirely rolled around a spool in a
cartridge body to its leading end is loaded in the film cartridge chamber
and the film is fed out through a film exit slit formed in the cartridge
body by the film feed mechanism. A guide portion for leading the leading
end of the film fed out through the film exit slit to the film feed
passage is provided at the film cartridge chamber side end of the film
feed passage. The guide portion includes at least an end guide surface
provided on the camera body. A part of the guide portion including a
corner portion between the end guide surface on the camera body and a
surface of the camera body extending from the film window is formed of a
smooth-faced gate member which is formed of a resin material containing
therein no fiber, while the camera body is formed of a fiber-reinforced
resin material.
Inventors:
|
Kobayashi; Kiyotaka (Saitama-ken, JP)
|
Assignee:
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Fuji Photo Optical Co., Ltd. (Saitama-ken, JP);
Fuji Photo Film Co., Ltd. (Kanagawa-ken, JP)
|
Appl. No.:
|
619339 |
Filed:
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March 21, 1996 |
Foreign Application Priority Data
Current U.S. Class: |
396/440; 396/387; 396/516; 396/538 |
Intern'l Class: |
G03B 017/02; G03B 017/26 |
Field of Search: |
354/203,212,288,275
|
References Cited
U.S. Patent Documents
5363166 | Nov., 1994 | Takahashi et al. | 354/288.
|
5521668 | May., 1996 | Ezawa | 354/203.
|
Primary Examiner: Mathews; A. A.
Attorney, Agent or Firm: Sixbey, Friedman, Leedom & Ferguson, P.C., Ferguson, Jr.; Gerald J.
Claims
What is claimed is:
1. A photographic camera comprising a film cartridge chamber, a film
take-up chamber, a film feed passage formed between a film window on a
camera body and a pressure plate on a camera back and a film feed
mechanism, a film cartridge in which a roll film is entirely rolled around
a spool in a cartridge body to its leading end being loaded in the film
cartridge chamber and the film being fed out through a film exit slit
formed in the cartridge body by the film feed mechanism, characterized in
that
a guide portion for leading the leading end of the film fed out through the
film exit slit to the film feed passage is provided at the film cartridge
chamber side end of the film feed passage, the guide portion including at
least an end guide surface provided on the camera body, and
a part of the guide portion including a corner portion between the end
guide surface on the camera body and a surface of the camera body
extending from the film window is formed of a smooth-faced gate member
which is formed of a resin material containing therein no fiber.
2. A photographic camera as defined in claim 1 in which said camera body is
formed of a fiber-reinforced resin material.
3. A photographic camera as defined in claim 2 in which at least the
surface of the gate member is formed of a low friction resin material.
4. A photographic camera as defined in claim 1 in which said guide portion
comprises an end guide surfaces respectively formed on the camera body and
the pressure plate.
5. A photographic camera as defined in claim 1 in which the surface of the
gate member facing the film feed passage is higher than the surface of the
camera body facing the film feed passage at the junction therebetween so
that no shoulder which can interfere with the leading end of the film in
the film feed direction is formed.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a structure of a photographic camera in which a
thrust type film cartridge (a film cartridge in which a roll film is
entirely rolled around a spool in a cartridge body to its leading end) is
loaded.
2. Description of the Related Art
In conventional photographic cameras, a film cartridge in which a roll film
is contained in a cartridge body with its leading end portion projecting
outside the cartridge body is used. Recently there has been proposed a
photographic camera in which a thrust type film cartridge is used as
disclosed, for instance, in Japanese Unexamined Patent Publication No.
6(1994)-110124. A photographic camera of this type will be referred to as
"a novel-type photographic camera", hereinbelow.
As shown in FIG. 6, the film cartridge 2 used in the novel-type
photographic camera comprises a cartridge body 3 formed of resin molding
halves bonded together and a photographic roll film entirely rolled around
a spool 6 in the cartridge body 3 to its leading end. A film exit slit 10
is formed in the side surface of the cartridge body 3 and a shutter member
11 is supported for rotation in the film exit slit 10 to open and shut the
film exit slit 10. The shutter member 11 extends in parallel to the spool
6 and is provided with a key 12 at its one end portion. The key 12 is
exposed outward at one end face of the cartridge body 3 and the shutter
member 11 is rotated between an opening position where it opens the film
exit slit 10 and a shutting position where it shuts the same by way of an
external shutter opening member which is adapted to be engaged with the
key 12.
Opposite ends of the spool 6 are exposed outward at opposite end faces of
the cartridge body 3 and are provided with keys 14. A drive mechanism on
the camera side is brought into engagement with the keys 14 to drive the
spool 6 to feed out and rewind the film.
Further, it has been proposed to provide a guide portion 50 for leading the
film 8 fed out from the cartridge body 3 to a film feed passage 32 formed
between a camera body 30 (film window) and a pressure plate 31 as shown in
FIG. 7. The guide portion 50 comprises a film end guide surfaces 51 and 52
which are respectively formed on the camera body 30 and the pressure plate
31. The leading end of the film 8 is brought into abutment against the
film end guide surface 51 on the camera body 30 and then led into the film
feed passage 32 under the guide of the guide surface 51.
It is desired that the wall thickness of the camera body 30 be as small as
possible in order to miniaturize the camera body. In order to reduce the
wall thickness of the camera body without reducing the strength, there has
been used fiber-reinforced resin containing therein a fiber material such
as glass fiber. By using such fiber-reinforced resin, strength of members
of the camera body is increased and the wall thickness of the moldings can
be reduced, which is advantageous in compactly forming the camera body.
However with the film guide structure described above, there is a fear of
the film surface scratching when the film 8 is guided into the film feed
passage 32 by the guide portion 50.
That is, as shown in FIGS. 8 and 9, when the film 8 passes the guide
portion 50 into the film feed passage 32, the film 8 runs on a corner
portion 54 between the guide surface 51 of the guide portion 50 and the
surface 53 of the camera body 30 opposed to the pressure plate 31.
Further, upper and lower inner rails 30a are formed on the camera body 30
to extend along the film feed direction as shown in FIG. 9 and the film 8
runs waving between the pressure plate 31 and the camera body 30 due to
curl of the film 8. Thus the film surface can be scratched by the edges of
the inner rails 30a at the corner portion 54 as indicated at A in FIG. 10.
That is, emulsion on the film surface can be scraped off along lines A.
Especially when the corner portion 54 is formed of fiber-reinforced resin,
the film surface is more apt to be scratched by the fiber material exposed
in the surface of the corner portion 54. The emulsion scraped off from the
film can adhere to the other part of the film or can enter the cartridge
body 3 and adhere to various parts in the cartridge body 3 when the film 8
is rewound, which can cause deterioration in quality of pictures and/or
drop-out when writing magnetic information if the emulsion adheres to a
magnetic head.
This phenomenon occurs when part of the surface of the camera body to be
brought into contact with the film 8 is not smooth or when the fiber
material is exposed in such part of the surface. Even if no fiber is
exposed in the surface of the camera body as it is molded, the fiber
material can come to be exposed when the surface is worn after repeated
feed of film.
SUMMARY OF THE INVENTION
In view of the+foregoing observations and description, the primary object
of the present invention is to provide a photographic camera in which
scratching of the film surface due to contact of the film with the corner
portion of the camera body can be prevented.
In a photographic camera in accordance with the present invention, a guide
portion for leading the leading end of the film fed out through the film
exit slit to the film feed passage is provided at the film cartridge
chamber side end of the film feed passage, the guide portion including at
least an end guide surface provided on the camera body, and
a part of the guide portion including a corner portion between the end
guide surface on the camera body and a surface of the camera body
extending from the film window is formed of a smooth-faced gate member
which is formed of a resin material containing therein no fiber.
It is preferred that the camera body be formed of a fiber-reinforced resin
material.
It is further preferred that at least the surface of the gate member be
formed of a low friction resin material.
Further it is preferred that the surface of the gate member facing the film
feed passage be higher than the surface of the camera body facing the film
feed passage at the junction therebetween so that no shoulder which can
interfere with the leading end of the film in the film feed direction is
formed.
In the photographic camera of the present invention, emulsion on the film
surface is not scraped off and the film surface is not scratched since the
surface of the corner portion is smooth and no fiber is exposed in the
surface of the corner portion, whereby quality of the pictures taken can
be ensured and various problems caused by emulsion scraped off the film
can be prevented.
Further since the camera body except the gate member can be formed of a
fiber-reinforced resin, the wall thickness of the camera body can be
reduced, whereby the camera body can be small in size and weight. Further
the resistance to feed of the film is reduced and the driving force can be
reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a horizontal cross-sectional view of a photographic camera in
accordance with an embodiment of the present invention,
FIG. 2 is a vertical cross-sectional view of the camera,
FIG. 3 is a fragmentary plan view partly in cross-section showing a part of
the camera,
FIG. 4 is a perspective view of the camera as viewed from the rear side
with the camera back removed,
FIG. 5 is an enlarged fragmentary cross-sectional view of the camera,
FIG. 6 is a perspective view of a film cartridge employed in the camera of
the present invention,
FIG. 7 is a cross-sectional view showing the film guide portion in the
conventional camera,
FIGS. 8 and 9 are views for illustrating the manner in which the film is
guided, and
FIG. 10 is a front view of a film for illustrating an example of scratch on
the film surface.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIGS. 1 and 2, a camera body 20 is provided with an exposure unit 23 at
its center and a cartridge chamber 24 and a film take-up chamber 25 on
opposite sides of the exposure unit 23. In the exposure unit 23, a taking
lens 21, a shutter mechanism and the like are incorporated. The exposure
unit 23 is retractable in the direction of the optical axis of the taking
lens 21 and is retracted when the camera is carried.
The film cartridge 2 is loaded in the cartridge chamber 24 with a bottom
lid 26 opened. When the film cartridge 2 is loaded in the cartridge
chamber 24, the spool 6 of the cartridge 2 is brought into engagement with
a fork 28 of a drive mechanism and at the same time, the film cartridge 2
is positioned with respect to the cartridge chamber 24 in the vertical
direction. Further the camera body 20 is provided with a shutter opening
member (not shown) which engages with the key 12 of the shutter member 11
and opens and closes the shutter member 11.
A film window 29 formed integrally with the camera body 20 and a pressure
plate 31 mounted on a camera back are disposed behind the exposure unit
23, and a film feed passage 32 is formed between the film window 29 and
the pressure plate 31 to communicate the cartridge chamber 24 with the
film take-up chamber 25. A guide portion 33 for guiding the leading end of
the film 8 fed out from the cartridge body 3 to the film feed passage 32
is provided on the cartridge chamber side end of the film feed passage 32
to be opposed to the film exit slit 10 of the film cartridge 2. Further as
shown in FIG. 2, a viewfinder 34 and a light projecting portion 35a and a
light receiving portion 35b of an AF unit are disposed above the exposure
unit 23.
A film take-up spool 37 driven by a motor 36 and a pair of film guide
plates 38 and 39 which press the leading end of the film 8 against the
film take-up spool 37 are provided in the film take-up chamber 25. The
motor 36 drives the fork 28 by way of gears or the like to feed out and
rewind the film 8. A light emitting portion 40, a capacitor 42 for strobe,
a battery 42 and a strobe circuit board (not shown) are incorporated in
the camera body 20 on the right side of the film take-up chamber 25.
As shown in FIG. 3, the guide portion 33 comprises a guide surface 51
formed on the camera body 20 and a guide surface 52 formed on the pressure
plate 31. The leading end of the film 8 fed out from the cartridge body 3
through the film exit slit 10 is inserted into the film feed passage 32
under the guide of the guide surfaces 51 and 52. The guide surfaces 51 and
52 may be inclined flat surfaces or curves surfaces. A part of the guide
portion 33 including a corner portion 54 between the guide surface 51 and
the surface 53 of the camera body 20 extending from the film window 29 is
formed of a smooth-faced gate member 45 which is formed separately from
the camera body 20 and is formed of a material other than the material of
the camera body 20.
As shown in FIG. 4, the film window 29 is formed behind the exposure unit
23 and a pair of inner rails 29a are disposed on upper and lower sides of
the film window 29 to extend in the transverse direction. The rails 29a
extend to the guide surface 51 of the gate member 45, and the surface of
the gate member 45 including the corner portions 54 of the inner rails 29a
are smooth-faced not to scratch the surface of the film 8. It is preferred
that the surface of the gate member 45 be formed of a material low in
friction.
The camera body 20 is formed, for instance, by molding of fiber-reinforced
resin such as fiberglass reinforced polycarbonate resin or carbon fiber
reinforced ploycarbonate resin. The gate member 45 is formed, for
instance, by molding of polycarbonate resin or polyacetal resin without
fiber. The polyacetal resin is excellent in lubricity. Further the gate
member 45 may be of metal or resin coated with lubricant. The surface of
the gate member 45 is resistant to wear against contact with the film 8
and is smooth (high in evenness) not to scrape off emulsion on the film 8.
The gate member 45 is fixed to the camera body 20 by means of screws 46
though it may be bonded to the camera body 20.
FIG. 5 shows the structure of junction between the gate member 45 and the
camera body 20. As shown in FIG. 5, the junction between the surface 53 on
the gate member 45 and the surface 53 on the camera body 20 is arranged
not to form a shoulder or projection which can interfere with the leading
end of the film 8 and prevent feed of the film 8. That is, an inclined
surface 47 is formed in the camera body 20 at the junction side end
portion so that the surface 53 on the camera body 20 does not become
higher than the surface 53 on the gate member 45 even if the thickness of
the gate member 45 or the camera body 20 fluctuates. It is preferred that
the corner at the upper end of the inclined surface 47 be chamfered or
rounded not to scratch the film surface.
When the film cartridge 2 is loaded in the cartridge chamber 24 and the
bottom lid 26 is closed, the controller of the camera drives the shutter
opening member to rotate the shutter member 11 to open the film exit slit
10. Then the controller drives the motor 36 to rotate the spool 6 in the
film feed direction by way of the fork 28, whereby the leading end portion
of the film 8 is fed out the cartridge body 3 through the film exit slit
10. Since the film 8 slightly curls so that the leading end is directed
toward the camera body 20, the leading end of the film 8 is brought into
abutment against the guide surface 51 on the gate member 45.
The leading end of the film 8 is smoothly led to the film feed passage 32
without being folded or jamming. When the leading end of the film 8
reaches film take-up chamber 25, the film 8 is pressed against the film
take-up spool 37, which is rotating, by the film guides 38 and 39 and is
wrapped around the spool 37. Thereafter the amount of film taken up by the
take-up spool 37 becomes larger than that fed out by the fork 28 and the
film 8 is taken up around the spool 37. When the first frame of the film 8
is brought to the film window 29, the take-up spool 37 is stopped. The
operation thereafter is the same as in the conventional camera and
accordingly will not be described here.
Even if the surface of the film 8 is brought into contact with the corner
portion 54 of the gate member 45 during feed of the film 8, emulsion on
the film surface is not scraped off and the film surface is not scratched
since the surface of the corner portion 54 is smooth and no fiber is
exposed in the surface of the corner portion 54, whereby quality of the
pictures taken can be ensured and various problems caused by emulsion
scraped off the film can be prevented.
The guide portion 33 may comprise only the guide surface on the camera body
20.
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